13,797 research outputs found
Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws
No full textThe movement and behaviour of particles suspended in aqueous solutions subjected to non-uniform ac electric fields is examined. The ac electric fields induce movement of polarizable particles, a phenomenon known as dielectrophoresis. The high strength electric fields that are often used in separation systems can give rise to fluid motion, which in turn results in a viscous drag on the particle. The electric field generates heat, leading to volume forces in the liquid. Gradients in conductivity and permittivity give rise to electrothermal forces and gradients in mass density to buoyancy. In addition, non-uniform ac electric fields produce forces on the induced charges in the diffuse double layer on the electrodes. This causes a steady fluid motion termed ac electro-osmosis. The effects of Brownian motion are also discussed in this context. The orders of magnitude of the various forces experienced by a particle in a model microelectrode system are estimated. The results are discussed in relation to experiments and the relative influence of each type of force is described
La Angelópolis, réplica de Jerusalén: una utopía novohispana.: Simbolismo espacial de El Alto, en la ciudad de Puebla de los Ángeles. Antropología. Boletín Oficial del Instituto Nacional de Antropología e Historia: Historia y antropología de Puebla. Num. 78 Nueva Época (2005) abril-junio
No full textBeaune, Colette, “De Telesphore a Guillaume Postel. La diffusion du libellus en France aux XIV eme et XV eme siecles”, en II Profetismo gioachimita tra cuatrocento e cincuecento, G. L.Potestá (ed.), Génova, Marietti, 1991.Benavente, fray Toribio de (Motolinía), Memoriales, ed., crítica, introd., notas y apéndice de, Nancy Jo Dyer, México, El Colegio de México, 1996.Biblia de Jerusalén, Nuevo Testamento, Bilbao, Desclee de Brower, 1976.Castellanos de García, Silvia, “Concretización de la ciudad de los Ángeles; su traza y paralelismo con la Jerusalén celeste, su escudo.Reflejo del joaquinismo-franciscano y del apocaliptisismo romano renacentista”, en Florensia. Bolletino del Centro Internazionale di Studi Gioachimiti, año XIII-XIV, nú. 13/14, 1999-2000, pp. 45-96.Chevalier, François, “Signification sociale de la fondation de Puebla de los Angeles”, en Revista Histórica de América, junio-diciembre, 1947.Delumeau, Jean, El miedo en occidente, México, Taurus, 2005._____________, Historia del Paraíso, vol. 2, Mil años de felicidad, México, Taurus, 2003.García Lastra, Leopoldo Agustín y Silvia Castellanos Gómez, La utopía angelopolitana, Jerusalén celeste de la Nueva España. La traza de El Alto como palimpsesto, Puebla, Secretaría de Cultura, 2005.Kirchhoff, Paul et al., Historia tolteca-chichimeca, México, Crítica/CIESAS/FCE, 1989.Lara, Jaime, City, Temple, Stage. Eschatological Architecture, and Liturgical Theatrics in New Spain, Notre Dame, University of Notre Dame Press, 2004.Le Goff, Jacques, La Baja Edad Media, en Historia Universal, t. XI, México, Siglo XXI, 1995.Lerner, Robert, Refrigerio dei Santi. Gioachino da Fiore e l´escatología medievale, Roma, Viella, 1995
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Principle Ward E. Tibbet of Saqinaw High School meets with forum members to sponsor Luis Castellanos trip to Europe (photograph)
No full textPrinciple Ward E. Tibbet of Saqinaw High School meets with forum members to sponsor Luis Castellanos trip to Europe
Analisi esplorativa grafica di dati economici. Breve guida didattica all'uso di R
No full textL'analisi esplorativa dei dati, oltre agli usuali scopi descrittivi, offre notevoli potenzialità interpretative quando si utilizzano le rappresentazioni grafiche che i programmi statistici di elaborazione automatica contengono in quantità sempre maggiore e con rese più accurate. Certe suggestioni grafiche possono fornire essenziali contributi per la costruzione dei modelli statistici ed indicare proprietà di sintesi necessarie alla loro validazione, basandosi sul contenuto informativo dei soli dati, prima ancora cioè della formulazione delle teorie sottostanti al fenomeno di studio.
In particolare il lavoro illustra brevemente e in forma didattica l'ambiente statistico con specifico riguardo all'analisi in Componenti Principali, all'analisi delle Corrispondenze ed all'analisi dei gruppi e mostra, attraverso l'applicazione ad uno studio reale di dati socio-economici tratto dalla letteratura, come l'interpretazione di opportune rese grafiche dell'analisi esplorativa possa condurre a risultati molto prossimi a quelli ottenuti con l'uso di modelli statistici sostenuti da teorie economiche
An Objective Bayesian approach for threshold estimation in the Peaks Over the Threshold model
No full textApré-eclâmpsia como um factor de risco independente para o transtorno do déficit de atenção com hiperatividade. Estudo caso-control. Bucaramanga, Colômbia
No full textEl trastorno por déficit de atención e hiperactividad es una condición mental que afecta a niños y adolescentes con prevalencia estimada de 5.3% en la población mundial y en Colombia de 19-24% en hombres y 10-12% en mujeres. Su etiología es multifactorial entre ellos la hipoxia, como un factor del medio ambiente uterino; presentándose en entidades como la preeclampsia, donde se ha considerado determinante en el desarrollo del trastorno por déficit de atención e hiperactividad; por eso es importante evaluar su asociación. Objetivo: Determinar la asociación entre el diagnóstico trastorno por déficit de atención e hiperactividad y el antecedente perinatal de preeclampsia. Metodología: Estudio de casos y controles retrospectivos de 404 casos de trastorno por déficit de atención e hiperactividad y 411 controles no emparentados sin el trastorno ni otros trastornos disruptivos del comportamiento. La evaluación psiquiátrica se hizo entre los años 2005–2011, mediante entrevista estructurada que incluyó indagar acerca del antecedente de PE en el embarazo de cada paciente. Resultados: El antecedente de preeclampsia se dio en el 3.7% de los pacientes con trastorno por déficit de atención e hiperactividad y en el 5.5% de los controles (OR 0.66, IC95% 0.34 – 1.29; p=0.221). Esta falta de asociación se mantiene luego de ajustar por género, ser adoptado, haber nacido por cesárea y edad de inicio del trastorno que llevó a consultar al paciente (OR 0.51, IC95% 0.22 – 1.17; p=0.115).Conclusión: No hubo significancia estadística entre el antecedente de preeclampsia materna y el trastorno por déficit de atención e hiperactividad en la muestra de los pacientes seleccionados. [Castellanos-Castellanos YA, Escobar-Sánchez M, Páez-Leal MC, Díaz-Martínez LA, Arias-Duran CA, Espitia-Orejarena DM, Forero-Parada JL. Preeclampsia y trastorno por déficit de atención con hiperactividad. Estudio de casos y controles. MedUNAB 2014; 17(1): 23-29]Attention deficit hyperactivity disorder is a mental disorder that affects children and adolescents. Its prevalence is 5.3% in the global population, in Colombia is 19-24% in men and 10-12% in women. Its etiology is multifactorial and hypoxia as a factor of the uterine environment; performing in entities such as preeclampsia, has been considered in the development of attention deficit hyperactivity disorder, been important to evaluate the association. Objective: Determine the association between attention deficit hyperactivity disorder diagnosis and perinatal history of preeclampsia. Methodology: Retrospective case-control study. 404 cases with attention deficit hyperactivity disorder and 411 unrelated controls without psychiatric or other disruptive behavior disorders. The psychiatric evaluation was made between 2005–2011 by structured interview, which will assess the obstetric history of mothers in search of preeclampsia. Results: The history of preeclampsia occurred in 3.7% of patients with attention deficit hyperactivity disorder and 5.5% of controls (OR 0.66, 95% CI 0.34 – 1.29, P= 0.221). This lack of association remains after adjusting for patient sex, if adopted, would have been born by caesarean section and age of onset of the disorder that led to refer the patient (OR 0.51, 95% CI 0.22 – 1.17, P= 0.115). Conclusions: There was no statistical significance between maternal history of preeclampsia and attention deficit hyperactivity disorder in the sample of selected patients. [Castellanos-Castellanos YA, Escobar-Sánchez M, Páez-Leal MC, Díaz-Martínez LA, Arias-Duran CA, Espitia-Orejarena DM, Forero-Parada JL. Preeclampsia and attention deficit disorder with hyperactivity. Case-control study. MedUNAB 2014; 17(1): 23-29
Estimating Geometric Parameters and States in Industrial Robot Manipulators Programming by Demonstration
No full textRejoinder: Bayesian checking of the second levels of hierarchical models
No full textHierarchical models are increasingly used in many applications. Along with this increased use comes a desire to investigate whether the model is compatible with the observed data. Bayesian methods are well suited to eliminate the many (nuisance) parameters in these complicated models; in this paper we investigate Bayesian methods for model checking. Since we contemplate model checking as a preliminary, exploratory analysis, we concentrate on objective Bayesian methods in which careful specification of an informative prior distribution is avoided. Numerous examples are given and different proposals are investigated and critically compared. © Institute of Mathematical Statistics, 2007
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